METAL DIFFUSION IN POLYMERS

The diffusive properties of copper, nickel, titanium and chromium have been studied in three polyimides and a fluoropolymer using both sputter-deposited surface film and shallow ion-implant sources. No measurable diffusion was found for either chromium or titanium, but diffusion constants and their thermal activation energies are presented for copper and nickel in each polymer. All the copper and nickel systems exhibit the clustering effects previously reported, and both atomic and cluster diffusion data are cited where possible. The metallic diffusion profiles from the surface films typically display three components: an initial subsurface distribution (which is actually due to the penetration of the surface by low energy ions during sputter-deposition), a shallow cluster distribution which contains the bulk of the diffusing material, and a deeper dilute atomic distribution.